The molding compositions disclosed in WO 99/57198 contain aromatic polycarbonates, rubber-modified graft copolymers and phosphorus-containing flame-retardants with the proviso that the fluorine content of the mix does not exceed 0.1 wt. %. Both linear and branched polymers may be used as the polycarbonate component in the compositions disclosed here. Particular advantages resulting from the use of branched types, in particular in combination with butadiene-free graft polymers, are not disclosed.
DE-A 3 149 812 discloses thermoplastic molding compositions with improved processability, which contain branched polycarbonates based on tetracarboxylic acid dianhydrides as the branching agent and graft polymers of the ABS, AES and ASA types. Advantages of ASA- and AES-containing compositions in comparison with the equivalent ABS-containing formulations are not disclosed.
EP-A 496 258 discloses compositions containing polycarbonate branched with special triphenolic compounds and other polymer components such as for example styrene resins, polyamide, polyolefins and rubber-type elastomers. EP-A 496 258 aims to provide polycarbonate compositions with good melt flowability, solvent-resistance and toughness.
U.S. Pat. No. 5,087,663 and U.S. Pat. No. 5,068,285 disclose branched polycarbonates or mixtures thereof containing linear polycarbonates in mixture with ABS or ASA polymers and MBS polymers, which have good blow-molding and thermoforming behavior.
JP-A 50 109 247 and JP-A 58 098 354 disclose polycarbonate blends containing AES, which contain liquid paraffin oil or plasticising additives as a further component. Special advantages resulting from the use of branched polycarbonate are not disclosed in this application.
The object of the present invention was to provide compositions with improved stress cracking resistance under the influence of chemicals. In particular, the invention relates also to flame-resistant compositions containing halogen-free flame-retarding additives.